Method of making tubular thermal insulation



Oct. 17, 1967 F. N. STEPHENS ET AL 3,347,725

METHOD OF MAKING TUBULAR THERMAL INSULATION '7 Sheets-Sheet 1 Filed Feb.27, 1963 0a. 17, 19m F, STEPHENS ET AL 3347;725

METHOD OF MAKING TUBULAR THERMAL INSULATION '7 Sheets-Sheet 2 Filed Feb.27, 1.963

M kw mm Q9 mm H Oct. 17, 1967 F. STEPHENS ET AL 3,347,725

METHOD OF MAKING TUBULAR THERMAL INSULATION Filed Feb. 27, 1963 7Sheets-Sheet I5 Oct. 17, 1967 STEPHENS ET AL METHOD OF MAKING TUBULARTHERMAL INSULATION 7 Sheets-Sheet! Filed Feb. 27, 1963 0d. 17, 19fi7 F.N. STEPHENS ET AL 3,347,725

METHOD OF MAKING TUBULAR THERMAL INSULATION '7 Sheets-Sheet 5 Filed Feb.27, 1963 mwm Q INVENTORS F/fiP/C V. 57? 5720/? J Ear/7 r2 Jasep/z TMar/60022144961 Jae/6 M My/a/ 4 ,1 I m- I 7 L l a:

ATrRNEYi k 5 m M a V5 46 T w 16 .4 M W7 3* F. N. STEPHENS ET METHOD OFMAKING TUBULAR THERMAL INSULATION Oct. 17, 1967 Filed Feb. 27, 1963 Oct.17, 1967 F. N. STEPHENS ET AL 3,347,725

METHOD OF MAKING TUBULAR THERMAL INSULATION 7 Sheets-Sheet 7 Filed Feb.27, 1963 d 04 /,T. 5 5 5 nw 5 .w/ 2 y fw Wm M? Fm W mwmw h} r0 ewc Waaw/ fiw O R m M m m a 6 M 73 5 J f A H m W V 3 w 4 5 a .6 z w v w w a w ew w e W w. m m on e m T 5% flu in F I F ZMN 4 w 1 V w N H W W 6 m a m n9 4 4 7 C M E E m 4 Q, A WW g g United States Patent 3,347,725 METHOD OFMAKKNG TUBULAR THERMAL INSULATION Frederick N. Stephens, Leawood, Kans,Stuart J. Burhans,

Kansas City, Mo., and Joseph T. Warkoczewski, (Everland Park, and JackM. Taylor, Kansas City, Karts, assignors, by mesne assignments, toQertain-Teed Products Corporation, Ardrnore, Pin, a corporation ofMaryland Filed Feb. 27, 1963, Ser. No. 261,408 3 Claims. (Cl. 156-184)This invention relates broadly to the manufacture of tubular thermalinsulation members composed of resin bonded fibers, for example, pipecovering and the like. More particularly, it deals with a method andapparatus for producing such articles which makes it possible toeliminate entirely the necessity of using individual molds forconforming and maintaining the article in the desired tubular shapeduring the curing of the binder.

It is the usual practice in the manufacture of pipe covering orinsulation ducts of carefully controlled density and dimensions to wrapa mat of intermixed fibers and uncured binder onto a mandrel, thenconfine the wound up mat and mandrel within a hollow mold conforming inshape and dimensions with the outside configuration of the article to beproduced, and apply sufficient heat to the confined mat as to result incuring of the binder and the setting of the product in its final shapeand condition. The article must then be removed from the mandrel andmold and the latter components returned to a station from which they canagain be used to form a new article.

The procedure brieflly described above, while quite satisfactory inobtaining a high quality product, still has numerous shortcomings,particularly in attempting to use it for high volume production and inthe manufacture of small diameter articles. For every given size ofarticle there must be provided a large quantity of identical mandrelsand molds, and complex equipment is required in order to maintain anoperation in which the mat is being used up as fast as it is produced.Each mandrel is required to be separable from the wind-up drivemechanism in order that the mandrel may travel with the mat through thecuring stage, and new mandrels must be positioned to receive the mat asit advances from the mat generating equipment. Moreover, if the articleis produced in different sizes, each size requires a full complement ofproperly dimensioned mandrels and molds.

One of the objects of the present invention is to provide a method ofproducing tubular articles of the character described which permits themanufacture of such articles to carefully control dimensions anddensities without, however, requiring the confining of the product on amandrel or within a mold during the final curing stage. This object, aswell as the others hereinafter set forth, is achieved in part throughthe novel steps of subjecting the internal wall of the wound, but yetuncured mat, while the latter is in place on the mandrel, and while themandrel is rapidly rotating, to a quick precuring and forming operationwhich has the result of producing on said wall a continuous tough shaperetaining skin which conforms, in inside dimension, to the finalconfiguration sought for the product. Simultaneously with the quickcuring of the skin, the mass of the mat is, by radial pressure,compressed to substantially the density desired in the final product.The curing of said internal periphery and the preforming of the mainbody proceeds only to a point where the internal skin is sufficientlystable as to give, and retain the product in its desired finalconfiguration. Thereupon the partially cured article (or preform) isremoved intact from the forming mandrel and transported in this state toa final stage in wihch that portion of the mat outwardly of the skin(which is the major portion thereof) is subjected to curing and finalforming. Since the partially cured article is, in and of itself, capableof substantially maintaining its shape during the necessary handlingthereafter, individual molds are not required, nor is any internalsupport necessary, and final curing is obtained by passing the articlethrough a curing zone completely unencumbered by any internal orexternal individual molds. It is a special feature of the invention thatfor any given size article we require but a single windup mandrel, andthat mandrel is required to support the mat for only a fraction of thetime interval necessary for complete curing of the article.

Another object of the invention is to provide a method for producingarticles of the character described which makes it possible to form andprepare the article for curing as fast as a single line of matgenerating equipment can supply blanks of uncured mat.

Yet another object of the invention is to provide a method for producingarticles of the character described which, in addition to the advantagesset forth above, makes possible the production of such articles from asingle line of mat generating equipment at a much faster time rate thanheretofore had been thought possible.

A further object of the invention is to provide novel apparatus forpracticing the method steps of the invention. In particular, among theprincipal objectives of the invention in this regard are (1) to provideequipment wherein the uncured mat is rapidly wound upon a mandrel andformed into the desired tubular shape without the use of special beltsor other bulky wrapping equipment; (2) wherein the portions of thewrapped mat immediately adjacent the internal surface is quickly curedto form a tough dimensionally stable continuous skin which is strongenough to maintain the shape and dimensions of the tubular article whenfreed from the mandrel, despite the uncured state of the binder in theannular portion outwardly of the skin; (3) wherein the uncured mat ispressure packed during winding and formation of the skin intosubstantially the final density and configuration desired for theproduct; (4) wherein the mandrel can rapidly be disengaged from thepartially cured article and quickly repositioned to receive a newportion of flat mat from the source of supply; (5) wherein the partiallycured preform is rapidly displaced from the wrapping station to clearthe way for incoming mat; (6) wherein the handling of the precuredarticle is gentle, yet rapid; and (7) wherein by simply changing thesize of the mandrel and/ or making a few minor adjustments, theapparatus is readily adapted to producing a wide variety of differentlydimensioned tubular members.

Other and further objects of the invention together with the features ofnovelty appurtenant thereto will appear in the course of the followingdescription.

In the accompanying drawings which form a part of the specification andare to be read in conjunction therewith, and in which like referencenumerals and symbols indicate like parts in the various views;

FIG. 1 is a schematic perspective view showing a typical production linefunctioning and constructed in accordance with the invention;

FIG. 2 is a greatly enlarged perspective view showing a lengthwisesection of a completed tubular article made in accordance with and onthe apparatus of the invention;

FIG. 3 is an elevational view taken from the input side of the wrappingand preforming assembly, portions of the framework, the conveyor beltsand its supporting rolls removed or broken away for purposes ofillustration;

FIG. 4 is an end elevational view taken from the left hand side of FIG.3;

FIG. 5 is a partially schematic central cross section through the mainoperating components of the wrapping and transfer assemblies, beingtaken generally along the line -5 of FIG. 3 in the direction of thearrows;

FIG. 6 is an enlarged end elevation of the transfer assembly, beingtaken generally from the lefthand end of FIG. 4;

FIG. 7 is an enlarge-d end view of one of the recip-- rocable mandrelheads, parts being broken away for purposes of illustration;

FIG. 8 is a sectional view through the head, being taken generally alongthe line 8-3 of FIG. 7 in the direction of the arrows;

FIG. 8a isan enlarged fragmentary partly sectional view illustrating theconnection between a mandrel section and its supporting hub;

FIG. 8b is a sectional view taken along line 88 of FIG. 8a in thedirection of the arrows;

FIG. 80 is a fragmentary enlarged sectional view illustrating theconfiguration of the mandrel section ends, the mandrel sections beingshown in slightly separated relationship;

FIG. 9 is a greatly enlarged fragmentary section through the mandrel,and looking at the floating bushing, being taken generally along theline 99- of FIG. 3 in the direction of the arrows;

FIG. 10 is a view corresponding to FIG. 9, but taken from the reverseside of the structure shown in FIG. 9;

FIG. 11 is a sectional view taken generally along the line 11-11 of FIG.10 in the direction of the arrows;

FIG. 12 is a greatly enlarged fragmentary cross section taken along line12-12 of FIG. 10 in the direction of the arrows; and

FIG. 13 is a schematic and diagrammatic view showing the control meansfor the invention.

General description Referring to the drawings and initially to FIG. 1,this figure illustrates schematically a typical continuous processembodying the features of the invention. Molten glass is fed through abushing to form downwardly moving primary fibers 21. The primaries maybe drawn uniformly by means of powered rollers 23 which bring theprimaries into a substantially planar relationship and feed them throughguide 24; A hot gaseous blast is delivered by blast throat 25transversely against the primaries to attenuate and form them into finemicrofibers which are directed toward and deposited in mat form as at260m i the foraminous conveyor 27. A suction box 28 is provided beneaththe upper flight of conveyor 27 to assist in obtaining proper deposit ofthe fibers on the conveyor. During the transition from the blast area tothe conveyor a heat reactive binder, preferably a thermosetting resin,is intermixed with the fibers, being delivered through distributing head29.'

The matted mixture of fibers and resin is delivered from the end of theforaminous forming conveyor 27 to a pickup conveyor 30, and a shear 31is utilized to cut the mat into blanks or pelts B of proper length forthe subsequent forming operation. This conveyor is driven at greaterspeed than the forming conveyor in order to effect a separation betweensuccesive blanks.

From the pickup conveyor the blanks B are successively transferred to.the input end of a still faster moving conveyor belt 32 which is a partof the wrapping and forming machine W to be described in full detailhereinafter. For the purposes of obtaining an initial and preliminaryimpression of the over-all apparatus, it sufiices to note at this pointthat belt 32 serves to advance the blank B toward and beneath and intocontact with a heated wrapping mandrel WM rapidly rotating in thecounterclockwise direction as viewed in FIG. 1, in such fashion that theportion of the mat that contacts the ,mandrel adheres thereto by thebinder in the mat. A conventional drive is provided for conveyor 32, forexample, an electric motor (not shown), connected with the left handroller support for the belt.

4 The mandrel ,WM serves to pick thepelt or blank from conveyor 32 andwrap it tightly into a spiral wrap around the mandrel. During its stayon mandrel WM, wrapped up blank has formed on its inner surface a skinof sufiicient thickness and integrity that when the mandrel is removedthe product will be generally self-supporting on its inside diameter.While the blank is wrapped on mandrel WM, a heated, .shiftable finishroller WR is moved from its solid line position of FIG. 1 into aposition spaced from the mandrel WM substantially equal to the desiredfinal wall thickness to be given the tubular product, and the mandreland roller are driven at synchronized speeds with the speed of belt 32for a selected period of time necessary to effect the formation by the.heated mandrel WM on the inside wall of the wrapped blank a thin, toughskin, as previously described. When the skin has been formed, andfollowing return of the roller WR to the broken line position, themandrel WM, which is composed of two oppositely reciprocable half lengthWMI and WM2, is separated from the tubular preform by pulling themandrel sections from the inside of the preform, as shown in brokenlines.

Once freed from the mandrel, the preform is directed to the spacedcradles C at'the upper end of a pivotal trans- I fer arm TA. Am TA ispivoted as at TAP and is'shifted clockwise by transfer arm cylinder TACto the upper flight of a formainious oven conveyor OC which serves toadvance the preform through the oven 0. The oven is of the type .inwhich heated air is blown vertically therethrough. During its movementthrough the oven the preform is reversely rolled against an upper staticscreen SC which is spaced above the upper flight of oven conveyor 0C adistance such that the portion of the preform outwardly of the interiorskin will be formed and held in its desired thickness. When it emergesfrom the oven, the product is completely cured and it can thereafter beslit longitudinally as taught in Stephens et al. Patent No.

2,778,759, to provide a structure which can be laterally applied to apipe to thermally insulate the same.

General information as to desired fiber diameters and binderconstituency for a satisfactory pipe covering of the type hereinenvisioned can be found in the aforementioned patent. The presentinvention deals principally with the process steps carried out andapparatus for effecting same in the wrapping and preforming section Wand transfer W to the oven conveyor 0C, and it is believed thatsufiicient information as to provide a preliminary understanding of theinvention and its manner of cooperation in a continuous process has beengiven.

However, as will become evident as the description proceeds, the subjectmatter of theinvention can also be used I in a process in which theuncured blanks B are preformed in one area and'subsequently transferredto another area and deposited by hand on the pickup conveyor 32.

The wrapping and preforming apparatus Referring now to FIGS. 3-7,inclusive, and more particularly at first to FIGS. 3 and 4, the wrappingand preforming machine W comprises a spaced pair of substantiallyidentical side members 40 which provide fore and aft supporting legs 41on each side of the unit. A deck 42 is secured to and extends betweenthe side members 40. On this deck is mounted a the main mandrel drivemotor 43, preferably electrically powered, which is connected through aclutch and brake mechanism 44 to a drive pulley 45. Pulley 45 is in turndrivingly connected with a driven pulley 46 secured to a hollow mainshaft 47 spanning between and journaled in the opposite side members ofthe machine by sleeve bearings 48. It will be noted that the sleevebearings project outwardly from the sidewalls.

The heated mandrel WM is supported between the two side members 40 ofthe frame, the two half lengths thereof being seen at WM1, ,WMZ in FIG.3. The inner ends 1 cable heads 50. Since the heads are substantiallyidentical in construction except for being right hand and left hand, thedetails of construction, which appear in FIGS. 7 and 3, of only one havebeen shown. The mandrel lengths WM1, WM2 extend respectively from theirconnections with the respective heads through floating bushings 80detailed in FIGS. 9-12, inclusive, and later to be described.

Each head 50 comprises a housing 51 which has near its lower end,oppositely and laterally extending ear portions 51a which containbearing sleeves 52. It will be noted from FIGS. 3 and 5 that supportedby and between the side members 40 and extending therefrom through theside members outwardly on opposite sides of the machine are parallelhorizontal guide rods 53, 54, respectively. These rods provide thenecessary support for the reciprocable heads 5t} during their movement,the bearing sleeves 52 being fitted thereover in a low friction slidingfit. The rods 53, 54 have at each end a tie bracket 55 (FIGS. 3 and 4)to which they are secured, and by which they are maintained at theirouter ends in spaced parallel relationship. Each bracket 55 has adepending leg 55a to which is secured an inwardly extending brace member56 which returns to and is secured to the side support for deck 42.These braces provide mountings for the outer limit switches OLSl andOLS2, and inner limit switches ILSl, ILSZ. These are engaged andactuated as the inner and outer limits of movement of the heads 50 arereached, and their function will later be described.

Reciprocation of the heads is effected by means of a pair of aligneddouble acting hydraulic cylinders 57 firmly secured to and supported bythe side frame members 40 and having the oppositely extending pistonrods 58. The fluid connections 57a, 57!) at the opposite ends of therespective cylinders are supplied from valves later to be described. Therods are connected inside the cylinders to the pistons 53a.

The manner of connecting the respective piston rods with theirassociated heads is best seen in FIG. 8. The head casing or housing 50is provided with a central tubular portion 59 which has inserted thereina tubular sleeve 60. Disposed within this sleeve is a piston 61 in theform of an annular ring keyed to rod 58 by a transverse pin 62. Thepiston 61 is circumferentially grooved to receive an O-ring 63 providinga seal between the piston and sleeve 50. End caps -64 are tightly fittedinto the opposite ends of sleeve ed, the inserted portions of the endcaps carrying 0 rings 65, and a seal 66 is provided around the rod 58 onthe insides of the caps. The sleeve 60, piston 61 and end caps 54 definetwo air cushion chambers 66a, 66b at opposite ends of the piston. Airlines 67a, 67b communicate respectively with these chambers, the flowbeing controlled by valves later to be described.

A cover 63 apertured to loosely receive the rod 53 is secured to theopen end of tubular portion 59, as by bolts 69. This holds the outer endcap 64 in place. The inner end cap 64 bears against an aperturedpartition 7 0 through which the rod 58 extends. The outer end of the rod53 has secured thereto a spring retainer disk 71 which is threaded ontoa stem 72. The stem 72 is connected with the rod 58 by a socket portion72a telescoped over the rod end and secured thereto by transverse pin73. A compression spring 7211 surrounds stem 72 and the adjacent portionof rod 58, bearing at its outer end against the retainer disk 71 and atits inner end against the partition 7%} through spring Washer 720. Theend cover 51b for the casing 51 includes an opening 51c aligned withdisk 71, and this opening is covered by a convex cup-like member 51d,permitting limited longitudinal movement of disk 71 relative to thehead.

The mandrel sections WMl, WM2 each extend from and are mounted to arotary shaft 74 which is supported by bearings 75 in a tubular housing76 at the upper end of the head 50' carrying the mandrel section. Theshaft 74 has secured and keyed to its outermost end a pulley 77 by whichthe shaft is driven, as will subsequently be seen.

The medial portion of shaft 74 is hollow and contains conductors (notshown) which are connected with four commutator rings 74a mounted on theshaft by insulators 74b. Brushes 74c provide electrical connectionbetween rings 74a and leads 74d.

Referring also to FIGS. 18a and 81), it will be seen that shaft 74terminates at its right hand end in an enlarged hub portion 73- providedwith an axial socket into which is inserted the plug-like member 79 atthe end of the mandrel section. The hub socket has longitudinal keyslots 78a into which fit key flanges 79a on opposed sides of theplug-like member 79 so that the mandrel section is connected with thehub for rotation therewith. A retaining collar R is threaded onto thehub to hold the member 78 therein with the mandrel section in alignmentwith the axis of rotation.

The plug-like member 79 carries internally an electric plug 79!) havingaxial blades 790 which are received in a jack 78b mounted within thehub. Internal conductors (not shown) connect commutator rings 74a withthe jack 78b. The blades of plug 79b are electrically connected with theheating and thermostat elements within the mandrel section byconventional conductors (also not shown).

The mandrel sections WMl, WM2 each comprise tubes 79d firmly secured toand extending from the member 79 and which contain a conventionalelectric heating element having built in thermal elements and in theform of a rod HR. At their outer ends the tubes respectively areprovided with cooperating tapered tip and socket portions as illustratedin FIG. 8c so that when the mandrel sections come into abutment, theywill interchange in axially aligned relationship.

As shown in FIGS. 9-12, inclusive, each mandrel section WMl, WM2,extends through a floating bushing 80, fitted into and extending fromone side of a bushing mounting and stripper plate 81. This plate is somounted to the frame side id as to have limited floating motion in aplane normal to the axis of the mandrel. To accomplish this it will benoted that the plate 81, which has a semicircular plan, is positionedwith its major portion overlying a semicircular cutout having edge 82formed in the side member 40. On the inner side of side member 4i), thecutout is enlarged radially to provide a surface 83 against which themargin of the adjacent base of the plate 81 seats, and an annularshoulder 84 spaced from the rim of the plate. The plate is connectedwith the side member 49 by bolts 85 having countersunk heads 85:: on theinside face of plate 81, so that their outer surfaces are flush with thesurface of the plate. The bolts extend loosely through oversizeapertures 86 in the side member and terminate in threaded reduceddiameter portions 85b onto which are threaded nuts 87. The oversizeapertures, plus the spacing between the edge of the plate and shoulder84 provide a free floating action for the bushing and plate which allowsa close tolerance to be provided between the bushing and mandrel withoutcausing binding in event of misalignment of the mandrel.

Synchronized rotation is imparted to the mandrel half sections WMI, WM2,through the drive mechanism now to be described. As previously noted,the main motor 43 drives a centrally disposed horizontal hollow shaft47. Extending from the lower end of each head 50 inwardly toward andaligned with shaft 47 is a splined shaft 88 which telescopically fitswithin the hollow main shaft 47. The latter is internally splined tomesh with the splines of shafts 88, and thus the splined shafts aredrivingly connected with the main shaft at all times duringreciprocation of the heads.

As noted from FIGS. 7 and 8, each splined shaft 88 is journaled inballbearing 89 carried by the casing 51. Secured to the outer end of theshaft is a drive pulley 90 around which is trained the drive belt 91.

Belt 91 extends upwardly in the housing, the opposed flights beingspaced on opposite sides of the shock absorber spring 72b, and istrained about the pulley 77 secured to the end of the mandrel hub shaft74. To provide means for effecting an efiicient driving connectionbetween pulleys and 77, an adjustable belt tightener having the pivotalarm 93 and belt engaging rolier 94 is positioned intermediate thepulleys. The arm 93 is pivoted on a pin 95 supported on the inside ofthe housing 51. An adjustment bolt 96 is threaded to a plate 97 on thehousing and engages at its inner end the side of arm 93, and provides ameans for controlling the tension in the drive belt 91.

As best seen in FIG. 5, the conveyor belt 32 is so positioned andsupported relative to the mandrel WM that it passes closely thereunderon a slight downward incline. The spacing of the belt from the mandrelisdetermined principally by the wall thickness to be given the tubularobject, the spacing being substantially equal to the wall thicknessdesired in the final product. Suitable support rollers 98, 99, 100 and101 have their ends journaled in conventional rotary bearings on theopposite side members 40. As earlier mentioned, belt 32 can beindependently driven by its own motor (not shown), connected with thelarge drive roller at the input end of the machine (see FIG. 1).

Supported above the mandrel WM and swingable toward the mandrel from thesolid line position of FIG. 5 to the broken line position is therelatively large diameter finish roller WR. This roller is of hollowmetallic construction and is heated by an internally disposed electricresistance heating rod 102 having the leads 102a seen in FIG. 4. Theouter surface of roller WR should be quite smooth.

The ends of the roller WR are rotatably journaled by and supportedbetween two depending spaced parallel arms 103. Each arm in turn isjournaled for pivotal movement about an axle 104 extending from one sideof a corresponding horizontal lift arm 105 at the side of the machine.

The lift arms 105 are each supported in cantilever fashion from theupper ends of vertical shaft 106 which extends through and is confinedfor up and down sliding movement, in upper and lower bushings 107, 108.The bushings are secured to the side members 40 of the machine. Eachshaft, 106 has near its upper end a gear rack segment 106a. Pinions 109mounted in common on a shaft 110 mesh with the respective rack segments.A hand wheel-110a (FIG. ,3) connected with one end of shaft 110 providesmeans for simultaneously raising or lowering the lift arms 105, and thuschanging the spacing of roller WR from the mandrel. A simple manuallyoperable set brake assembly of conventional construction is shown at111, the brake assembly having the vertical operating shaft 112. Thebrake assembly 111 cooperates with shaft 110 and provides means forlocking the shaft 110 against rotation so as to preserve a desiredspacing between the roller and mandrel.

Pivotal displacement of roller WR from one position to another isaffected by the actuation of double acting air cylinders 113, one eachbeing secured to the upper surface of a lift arm105. As best seen inFIGS. 4 and 5, each cylinder has a piston rod 113a which is connected bythe usual clevis joint with an upward extension 103a on its associatedroller carrying arm. Air lines 113b, 1130 are provided at the oppositeends of the cylinders for connection with a control valve later to bedescribed.

The roller WR is driven by an electric motor 116. The motor is supportedon a cross piece 117 extending between and secured at its ends to liftarms 105. The motor drives a speed reducer 118 having the sprocket 119on its output shaft. A first chain 120 is trained about sprocket 119,and about one sprocket of a two sprocket idler hub 121 which isrotatably journaled around axle 104 through lift arm 105. The othersprocket of the idler hub is connected with a driven sprocket 122 bymeans of a second chain 123.

Sprocket 122 is connected with the roller WR and is operable to rotatesame. Since hub 121 is rotatable on the pivot axis of arms 103, it willbe evident that drive to the roller is maintained as the roller ispivoted between its up and down positions.

In order to facilitate adjustmentof the elevation of the lift arms 105,the lift arm assembly is counterbalanced by means of tension spring 124having one end connected with cross member 117, as by hook 124a, and theother end to a suitable bracket 40a on the frame of the machine.

The roller assembly also includes the roller cleaning brush 125. Thisbrush preferably comprises a rod 126 disposed parallel with the rollerWR and rotatably supported for limited rotation about its own axisbetween the outer ends of lift arms 105. The brush tufts are directedtoward the roller and are so positioned as to engage the surface of theroller and clean same when the roller is brought to the up position. Ahandle 126a. is keyed to brush and can be employed to rotate the brushto a.

point where foreign matter collecting thereon can in turn be removed byplucking or scraping it therefrom.

It may be best at this point to describe the general operation ofwrapping and preforming apparatus somewhat further. In preparing theapparatus for operation, the

drive motor for belt 32 is started, the belt being driven at constantspeed. The mandrel motor 43 is also started and isset to a speed atwhich the surface speed of the mandrel is substantially greater than thelinear speed of the conveyor belt 32. The mandrel sections are heated toa surface temperature sufficiently high that when the uncured pelt Bcomes into contact therewith, the binder in the pelt will preliminarilyadhere directly to the mandrel with sufficient integrity as to cause themandrel to Whip the pelt ahead and from its position on conveyor belt 32and wrap it tightly about the mandrel in a plurality of wound-on layers.For the ordinary binders a temperature of 750 F. to 1000 F. has provedsatisfactory, and a mandrel speed range of (for mandrel diametersbetween /2 inch and 1 inch) 100 r.p.m. to 450 rpm. with a belt speed ofaround 65 feet per minute.

During the wrapping of, the pelt on the mandrel, the

motor 116 continuesto drive roller WR, but the roller is in the upposition, the, cylinders 113 being actuated in a direction to hold theroller arms 103 up. The speed of the roller WR is set so that itsperipheral speed at the surface is substantially equal to the beltspeed.

As the ,pelt is wrapped about the mandrel, the drag exerted by the belt32 on the trailing end of the pelt tends to pull the pelt into a tightwrap. In other words, since the mandrel in effectpulls the peltforwardly relative to the belt, there is an inertia reaction, as well asfrictional drag, both of which serve to put the trailing portion of thepelt in tension. This causes the wound portion to be wrapped fairlytightly on the mandrel at a density much greater than that of theadvancing pelt. Obviously, the wrapped density is a function of therelative speeds between the mandrel and the belt.

When the pelt is completely wrapped on the mandrel,

the speed of the mandrel is reduced to what is hereinafter termed thefinish speed. Change in speed is madeby controlling motor 43. The finishspeed is one at which the peripheral speed of the wrapped build-up onthe mandrel is substantially equal to the linear speed of belt 32. Atthe same time, air cylinders 113 are actuated to swing roller WR down tothe broken line position, in which the surface of the roller is spacedat its nearest point to the mandrel a distance equal to the desiredfinal thickness. of the tubular article. Rotation of the mandrel androller is continued and the mandrel, belt and roller cooperate to pressand preliminarily form the outer surface into a uniform cylindricalshape. The roller WR is heated to a temperature.

. which is sufficient to prevent adherence of the outer surface to theroller, 9. recommended temperature range be ing 500 F. to 600 F.

The article is retained on the mandrel until such time as the binder.adjacent the mandrel has cured sufiiciently to form a thin, toughinternal skin or core as shown at CR in FIG. 2. We have found that thiscan be accomplished in a matter of seconds, to seconds being ample withthe mandrel temperatures noted earlier. The major portion of the binderin the build-up does not cure out during this interval. However, theinternal skin becomes strong enough to provide the necessary internalsupport to maintain the article in tubular shape when the mandrel iswithdrawn.

When the curing of the internal core has taken place, roller WR is againraised by actuating cylinders 113. The mandrel sections WMl, WM2 arethen withdrawn by actuating hydraulic cylinders 57 in a direction toforce heads 50 outwardly to the broken line positions of FIG. 3. Sincethe heads 50 carry the mandrel sections, the latter are withdrawn fromthe opposite ends of the article and it is free to move downwardly andforwardly toward the transfer apparatus TA shown in FIG. 1.

Sharp clean separation of the mandrel sections from the core of thearticle is achieved in part through the special manner of connection ofeach of the heads 50 with its thrust rod 58. Referring again to FIG. 8,it will be noted that as the rod 58 starts outwardly, the inertia of thehead, as Well as any internal resistance in the article to withdrawal ofthe mandrel section tends to hold the head stationary. Initially, bothchambers 66a and 6611 are at atmospheric pressure. As rod 58 startsoutwardly (which is a rapid movement), pressure builds up in chamber66a. However, a low pressure pop-off valve 67c relieves this pressureand allows the piston to strike sharply against the inner end cap 64 andprovide a sharp jar or impact on the head at the start of the mandrelmovement.

When the head 50 reaches its outer limit of travel, the inertia of themandrel section and its associated parts causes sleeve 60 to shift tothe left on piston 61. The shock absorbed by spring 72b and by thepressure build-up in chamber 66b. On the return stroke, piston 61 islocated at the extreme right hand end of the sleeve cylinder, and soobviously when the head reaches the inner limit of travel, theconfronting inner ends of the respective mandrel sections will be stillseparated. At this point, valve 67d is cycled to successively introducepressure to chamber 66a and reconnect it with the atmosphere. Air willthereafter slowly bleed from chamber 66a at a controlled rate throughrestriction 67 and the ends of the mandrel sections are thus permittedto come gently together during the last phase of inward travel.

While we have found that clean separation of the mandrel sections fromthe tubular article can be achieved while the mandrel is still turningat its lower finish speed, it may be desirable in some cases to stop themandrels entirely prior to actuation of the heads and to restart themandrel when the heads have been returned to the normal position. Thiscan be accomplished by providing appropriate controls on the brake andclutch mechanism between motor 43 and the main drive'shaft 47.

Upon return roller WR is still in the up position and the unit is readyto receive, wrap and preform another blank or pelt of green or uncuredmat in the fashion described above.

T he transfer and final cure apparatus When the cured article isdetached from the mandrel, as previously noted, it drops downwardly andforwardly toward the transfer apparatus TA and into the spaced cradles Cthereof.

The cradles C are generally V-shaped and are carried at the upper end ofa generally triangular frame having the horizontal leg 127 to which thecradles are secured, and the converging side legs 128. The latter aresecured at the lower ends to a sleeve 129 surrounding and keyed to anaxle 130. Axle 130 is journaled at its opposite ends in bearings 131,which in turn are supported on a rigid base 132 which may convenientlybe secured to and supported from the wrap up frame.

Sleeve 129 has extending radially therefrom a pair of spaced lugs 133.Between the outer ends of these lugs is pivotally connected, as by pin134, the outer end cap 135a of a piston rod 135. Piston rod 135 formspart of the double acting air cylinder TAC having air connections 136a,1361) at the opposite ends of the cylinder. The cylinder body ispivotally connected with base 132 by pivot pin 137.

The transfer apparatus is so constructed that cradles C arereciprocating between the solid and broken line positions of FIG. 5. Inthe up or broken line position the cradles are below and slightly inadvance of the nose of conveyor 32 and in position to receive thetubular article as it descends over the nose. Because of the broadV-shape of the cradles the article will align itself in the cradles.When piston rod 135 is retracted, the cradles C are swung in an arctoward the oven conveyor 0C and gentle deposit of the article thereon byrolling off the legs of the cradles takes place.

Because of the construction and operation of the cradles, the article isdelivered to the oven conveyor with its axis normal to the path ofadvance or parallel with the oven conveyor support rollers. It is thusin proper position to be carried forward under the static screen SC(FIG. 1) and to move thereunder in reverse rolling fashion through thelength of the oven during final cure.

T he automatic control system To effect automatic sequential control ofthe wrap-up and perform apparatus and to properly relate it to thetransfer mechanism, the arrangement and circuitry shown in FIG. 13 canbe utilized.

The control circuit is energized from a pair of terminals 200, 201 whichmay be connected to any appropriate source of potential (not shown).

The control operation is commenced by momentarily closing the startswitch 292 which energizes the start relay SR and closes the starterrelay contact SR1 in the circuit to hold the start relay closed uponrelease of the start switch. This also serves to energize theincandescent lamp 203 which provides a visual indication that thecontrol circuit is energized. It will be understood that at this timedrive motor 43 has already been separately energized and is driving themandrel WM at the wrapping speed, motor 116 is rotating roller WR at thewrapping speed, the conveyor 32 is being driven at its pelt feedingspeed and the hydraulic and air systems are set so that the componentsare in the positions shown in solid lines in the drawings.

Upon closing of the start switch, SR2 closes to arm the circuit, and anincandescent lamp 204 is energized, this lamp forming part of thephotoelectric control having the hototube circuit 205. This circuit isunder the control of the photoelectric tube 206 (FIGS. 1 and 4) which ispositioned to one side of belt 32 ahead of the mand'rels WM. The lamp204 is on the opposite side of the belt and arranged so that its beam isreceived on the phototube. The phototube circuit is not shown in detailsince it is well known, it being sufficient to observe that it is suchthat whenever light from lamp 204 falls on the photoelectric tube 266,the phototube relay winding R6 is not energized. Whenever the lamp beamis interrupted by the leading end of an advancing pelt B, thedeenergization of the tube causes energization of relay winding R6 byclosing photocell contact PC1, assuming that normally open relay contactR171 is closed. If the condition of the unit is normal this contact willbe closed since its winding R17 is controlled by the innerlimit switchesILSl and ILS2 which are closed when the heads 50 are in their innermostpositions.

Upon the energization of winding R6 it is locked in by the closing ofR64. At the same time, its second contact R6-2 closes, thus energizingtimers T1, T2, T3.

The timers each are of the known type that upon energization begintiming out and at the end of the selected time interval causeenergization of a timer relay. The respective timer relay windings areindicated at TRI, TR2, TR3.

The timer T2 is the first to time out, closing contact TR21 andenergizing the windings RR and TAR of the solenoid actuated valves 207and 208. Valve 207 controls the air supply to the heated rolleractuating cylinders 113 and valve 208 controls the transfer arm cylinderTAC. Energization of the solenoid windings causes each valve to effectthe shift of the roller WR and transfer arm to the broken line positionsof FIGS. 1 and 5. The timed interval need only be sufficient as topermit the pelt B to be wrapped on the mandrel before the roller movesto the broken line, or down position.

Timer T3 times outat about the same time and energizes its relay windingTR3, thereupon closing contact TR'3-1 whichcontrols a speed changecircuit through the mandrel motor feed control MMSC. The latter controlsthe, speed of mandrel drive motor 43 and operates, when energized, toreduce the speed of the mandrel to the finish speed earlier described. Aconventional speed controller may be used and no further detail isbelieved required.

Next in sequence, timer T1 times out, energizing its relay winding TR1and closing its contact TR1-1 in the circuit to a timer T4 and startingsame on its time cycle. Timer T4 times out, and as it does it energizesits winding TR4, thus closing contact T R4-1 in the stopping circuit.Relay windings R28, R B, RSA and R8 are thereupon energized. It will benoted that relay winding R8A closes a contact RSA-l and establishes acircuit around contact TR41, thus locking in the windings in thestopping circuit. The energizing of winding R8 opens a normally closedcontact R8-1 in the start circuit thus deenergizing and dropping outwindings R6 and RSA. The dropping out of relay R6 opens contacts Rd-land R6-2 breaking respectively the locking circuit and the circuitsthrough timers T1, T2 and T3. The timers thereupon reset for anothercycle. At the same time, contact TR21 in the roller circuit opens, andthe heated roller and transfer arm are returned to the solid linepositions by operation of valves 207 and 208.

The energization of relay winding R28 closes the contact R28-1 in thecircuit of timer T8 and starts the time cycle of T8. As the latter timesout, it energizes winding TRS and closes contact TR8-1, which in turnenergizes relay winding R29. This winding closes contact R29-1 in themandrel circuit, and since contact RS-2 has already been closed. (uponenergization of Winding R8), the valve solenoid MR1 is energized,shifting the mandrel position control valve 210. The valve 210 controlshydraulic fluid flow to the double-acting cylinders 57. When it isactuated by solenoid winding MR1, the fluid is directed into lines 57a(FIG. 3) thus forcing heads 50 outwardly as pre viously described andseparating the mandrel sections. Normally,the valve is maintained in theopposite position by solenoid winding MR2; however, it will be notedthat enegization of relay winding R8 at the end of the T4 time cycleopens the contact RS-S and thus winding MR2 is deenergized prior to theenergization of winding MR1.

When the mandrel heads 50 come out, limit switches OLSl and OLSZ willclose. This results in energization of relay winding R18 and openscontact RIG-1 in the stopping circuit. However, the stopping circuitwill remain energized through the normally closed contact TR19-1.

The contact TR19-1 is controlled by the winding TR19 of timer T19. T19is energized by the closing of con tact R18-2in response to the mandrelheads reaching theoutermost position. The timer T19 operates to delaythe return of the mandrel heads sufiiciently as to permit the tubulararticle be cleared from the withdrawn mandrel sections and drop into thetransfer arm cradle TAC. When T19 times out, its winding TR19 isenergized, opening the normally closed contact TR191 in the stoppingcircuit.

When timer T19 times out, the. normally closed contact TR19-1 in thestopping circuit opens, thus dropping out relay windings R23, RSB, RSAand R8 and breaking the locking circuit through contact R8A-1. When thestopping circuit relay windings drop out, relay winding R29 isde-energized (through opening of contact RS-l) and energization ofmandrel relay winding MR2 occurs. The latter serves to reset valve 210to its original position, causing the head cylinders to return the heads50 toward the original position. As the heads close the innerlimitswitches 11.51 and ILS2 are closed, and the air cushion valve 67-d isactuated, as earlier described, by

energization of winding ACR. Winding R17 is also closed and contactR1'7-1 is thereupon closed. The control circuit is now ready for anothercomplete cycle which is instituted when the next piece of green mat orpelt interrupts the beam to the phototube.

From the foregoing, it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forthtogether ;with other advantages which are obvious. and which areinherent to the structure.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.-

As many possible embodiments may be made of theinvention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings isto beinterpreted as illustrative and not in a limiting sense.

Having thus described ourinvention, we claim:

1. In a method of manufacturing tubular articles from a flexible matoffibers and intermixed uncured heat re-v active binder, the steps ofrapidly rotating a highly heated mandrel about its longitudinal axis,advancing said mat laterally toward and into contact with said mandrel,adhering a portion of the mat to said mandrel by the binder in said matwhereupon said mat is wrapped rapidly and tightly about the mandrel bythe rotation of the mandrel to form a tubular build-up, maintaining saidbuild-up on the mandrel a period of time sufficient to form a cured,dimensionally stable skin on the interior surface of the build-up,withdrawing the mandrel from the build-up,

and further heating the. mandrel-free build-up to cure the remainder ofthe binder.

2. A method as in claim 1 including the step of slowing the rate ofmandrel rotation, after formation of the build-up, to a value at whichthe, peripheral speed of the build-up is substantially equal to thespeed of the support.

3. A method as in claim 1 wherein the mat is advanced on a movingsupport toward said mandrel and the peripheral speed of the mandrel isgreater than the speed of the support.

References Cited UNITED STATES PATENTS 2,503,041 4/1950 Greene 156.184 X3,063,887 11/1962 Labino 156-446 X 3,093,532 6/1963 Miller et al.156-484 X 3,121,253 2/1964 Varrial 156-455 X EARL M. BERGERT, PrimaryExaminer.

P. DIER, Assistant Examiner.

1. IN A METHOD OF MANUFACTURING TUBULAR ARTICLES FROM A FLEXIBLE MAT OFFIBERS AND INTERMIXED UNCURED HEAT REACTIVE BINDER, THE STEPS OF RAPIDLYROTATING A HIGHLY HEATED MANDREL ABOUT ITS LONGITUDINAL AXIS, ADVANCINGSAID MAT LATERALLY TOWARD AND INTO CONTACT WITH SAID MANDREL, ADHERING APORTION OF THE MAT TO SAID MANDREL BY THE BINDER IN SAID MAT WHEREUPONSAID MAT IS WRAPPED RAPIDLY AND TIGHTLY ABOUT THE MANDREL BY THEROTATION OF THE MANDREL TO FORM A TUBULAR BUILD-UP, MAINTAINING SAIDBUILD-UP ON THE MANDREL A PERIOD OF TIME SUFFICIENT TO FORM A CURED